1. Field of the Invention
This invention relates generally to nuclear power plants and more particularly, to a method and apparatus enabling a user to perform estimated crack behavior calculations for the user's nuclear reactor.
2. Related Art
Water chemistry characteristics in a nuclear reactor such as boiling water nuclear reactor may be used to predict crack growth behavior by using an existing, fundamental crack growth behavior model. The model was derived from detailed engineering analysis of historical data and historical behavior, so that crack growth behavior estimation can be performed accurately using water chemistry characteristics and materials characteristics. Current evaluations, however, require all crack growth assessments to be done by different individuals, typically by hand, upon user request. Moreover, a complete crack growth analysis done by specialists is both expensive and time consuming.
Recently, an automated method for crack behavior prediction has been developed. Referring to commonly assigned U.S. application Ser. No. 2001-0053965 to Horn et al., entitled “Method And Apparatus For Automated Crack Behavior Prediction Determination”, there is an automated method for predicting component crack behavior in a nuclear reactor, in which water chemistry characteristics are input over a computer network, and a crack growth behavior model is accessed for predicting component crack behavior according to the input water chemistry characteristics. A crack growth prediction profile, or crack growth derived result according to the analysis is then output to a user, via the computer network.
In Horn et al., a user connects to a system server on the internet for example. The user inputs characteristics such a frequency, stress intensity, crack tip strain rate, water chemistry and environmental parameters such as conductivity, corrosion potential, oxygen level, etc. to the server. When all the inputs are complete, the server accesses a crack behavior model that predicts component crack behavior according to the characteristics input by the user. The server, via a suitable graphical user interface, outputs a crack growth prediction profile, which may represent a real time crack growth prediction. This is a “real time” evaluation in the sense that it uses current reactor plant data in the context of historical data to project future behavior, a process that can be updated at any time to include new plant data. The output is a graphical representation of a crack growth rate on a chart or graph, for example
As noted above, a full crack growth analysis is both expensive and time consuming, and even with the above automated system, a user must input a substantial number of parameters in order to receive a crack growth prediction profile from a single crack behavior model. Further, monitoring personnel from nuclear reactors need a mechanism to perform a superficial scoping analysis of a particular crack very quickly, in order to determine whether or not a full analysis is required. Accordingly, potential users require a method by which they can quickly access and review all current cracks in their nuclear reactor over a relatively short period of time, at their convenience, and at minimal cost and time to the user.